Question

我正在获取'Client' is not convertible to 'AFOAuthSignatureMethod'这一行：if self.selectedClient == client {在cellForRowAtIndexPath方法的正文中。

不知道为什么要比较AFOAuthSignatureMethod。一个Xcode错误？

Client.swift

import Foundation

class Client {
    var id : String!
    var organization : String!

    init(id: String, organization: String) {
        self.id = id
        self.organization = organization
    }
}

SelectController.swift

import UIKit

class SelectController: UITableViewController, NSXMLParserDelegate {
    // MARK: Properties

    var clients : [Client] = []
    var selectedClient : Client!

    var elemName : String!
    var clientId : String!
    var organization : String!

    required init(coder aDecoder: NSCoder!) {
        super.init(coder: aDecoder)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        var defaults = NSUserDefaults.standardUserDefaults()
        let accountData = defaults.objectForKey("credentials") as NSDictionary!

        if accountData == nil {
            let authController = self.storyboard.instantiateViewControllerWithIdentifier("AuthController") as AuthController
            self.navigationController.pushViewController(authController, animated: false)
        }

        if clients.count > 0 {
            self.tableView.reloadData()
        } else {
            let accountName = accountData["accountName"] as String
            let key = accountData["key"] as String
            let secret = accountData["secret"] as String

            let baseURL = "https://\(accountName).freshbooks.com"

            var token = AFOAuth1Token(key: key, secret: secret, session: nil, expiration: nil, renewable: true)

            var freshbooksClient = AFOAuth1Client(
                baseURL: NSURL.URLWithString(baseURL),
                key: consumerKey,
                secret: consumerSecret
            )
            freshbooksClient.accessToken = token
            freshbooksClient.signatureMethod = AFOAuthSignatureMethod.AFPlainTextSignatureMethod

            let requestBody = "<?xml version=\"1.0\" encoding=\"utf-8\"?><request method=\"client.list\"></request>"

            var request = freshbooksClient.requestWithMethod("POST", path: "/api/2.1/xml-in", parameters: nil)
            request.HTTPBody = requestBody.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)
            request.HTTPMethod = "POST"

            var operation = AFXMLRequestOperation(request: request)
            freshbooksClient.registerHTTPOperationClass(AFXMLRequestOperation)

            operation.setCompletionBlockWithSuccess(
                { (operation : AFHTTPRequestOperation!, responseObject) in
                    var parser = responseObject as NSXMLParser
                    parser.delegate = self
                    parser.parse()
                },
                failure: { (operation, error) in
                    println("Error: " + error.description)
                }
            )

            operation.start()
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView?) -> Int {
        return 1
    }

    override func tableView(tableView: UITableView?, numberOfRowsInSection section: Int) -> Int {
        return clients.count
    }

    override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell

        var client = clients[indexPath.row]
        cell.textLabel.text = client.organization

        if self.selectedClient == client  {
            cell.accessoryType = UITableViewCellAccessoryType.Checkmark
        } else {
            cell.accessoryType = UITableViewCellAccessoryType.None
        }

        return cell
    }

    override func tableView(tableView: UITableView!, didDeselectRowAtIndexPath indexPath: NSIndexPath!) {
        self.selectedClient = clients[indexPath.row]
        tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.None)
    }

    // MARK: Navigation

    override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {

    }

    // MARK: Parser

    func parser(parser: NSXMLParser!, didStartElement elementName: String!, namespaceURI: String!, qualifiedName qName: String!, attributes attributeDict: NSDictionary!) {
        elemName = elementName
    }

    func parser(parser: NSXMLParser!, didEndElement elementName: String!, namespaceURI: String!, qualifiedName qName: String!) {
        if elementName == "client" {
            var client = Client(id: clientId, organization: organization)
            clients.append(client)
        }
    }

    func parser(parser: NSXMLParser!, foundCharacters string: String!) {
        let data = string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
        if (!data.isEmpty) {
            if elemName == "client_id" {
                clientId = data
            } else if elemName == "organization" {
                organization = data
            }
        }        
    }

    func parserDidEndDocument(parser: NSXMLParser!) {
        // Sort clients alphabetically
        clients.sort({ $0.organization < $1.organization })

        self.tableView.reloadData()
    }
}

Answer 1

错误消息具有误导性。问题是等于运算符==不是为

中的Client课程定义

if self.selectedClient == client  { ... }

可能的解决方案：

请改为使用标识运算符===：
```
if self.selectedClient == client  { ... }
```
这将检查对象引用是否都引用同一个对象实例。
让您的班级继承自NSObject：
```
class Client : NSObject { ... }
```
然后该类从isEqual:继承NSObject方法（也进行比较对象指针，除非被覆盖）。

为您的班级实施==，例如：

func ==(lhs: Client, rhs: Client) -> Bool {
    return lhs.id == rhs.id && lhs.organization == rhs.organization
}

在你的情况下，第一个解决方案可能是正确的。

错误的Swift类型转换尝试完全不同的对象类型

1 个答案: